Winter gardening.

Tags

daffodil, jasmine, water hyacinth, whitefly

The indoor plants are ticking over, I guess. The jasmines (Jasminum sambac) have their usual winter infestation of whitefly, so I broke out the insecticidal soap a few days ago. The references specify to use soap and not detergent; being of a curious (skeptical) nature I experimented with detergent in previous years and guess what! It doesn’t work. I imagine it’s because the chemical properties are different (soap is a mixture of fat and alkali; detergent is a petrochemical byproduct).

The reason soap works on insects is because insect exoskeletons (made of chitin) are not inherently waterproof. To prevent dehydration, they exude a waxy cuticle. Soap dissolves this cuticle and the insect dries out. Detergent has a different chemical activity, which I imagine doesn’t remove the wax. Chemistry was a long time ago for me, so that’s as far as I can go without looking it up.

Anyway, in another experiment, the plant bulb did not prove to be any better than a standard incandescent bulb. The water hyacinths (Eichhornia crassipes) growing under a table lamp did just as well with either bulb. I’ve also successfully maintained tropical plants under a halogen desk lamp. Somehow this was the result I’d expected; the bulb was a 60-watt Phillips Agro-Lite bulb. Possibly a different brand might give different results. I do know that regular incandescents are not enough to raise seedlings.

Finally, I remember now why I never forced paperwhite daffodils (Narcissus tazetta) indoors since the first time. First, they flop over. Second…the smell. Oh gods the smell.

Winter lemondeath

Tags

jasmine, lemon, lemon grass

Well, the winter houseplant casualties began a couple weeks ago (Merry f**king Christmas) with my original ‘Meyer’ lemon plant (Citrus x meyeri) and one of the lemon grass plants (Cymbopogon citratus). ‘Meyer’ lemons are often touted as being well-suited as indoor plants, but mine always suffered in winter and this year it finally gave up. Fortunately, two years ago I took a cutting from it, and it’s doing fine. On the bright side, this way I get to train and shape the young plant from the beginning.

I think the lemon bush had the hardest time coping with the dry air. People talk/think more about the lack of light and low temperatures, but humidity is vital to most houseplants too. Unfortunately, central heating is very effective at stripping the moisture from the air, and most North American houses in winter are extremely dry. The lemon bush was by then too big for my usual humidifying methods to compensate, I think. There could be other factors, too.

As for the lemon grass, that was probably a combination of low light and being too close to the front door for too long (tropical plant in front of a cold draught every time the door opened). The other one is doing fine in the window, and they’re easy to propagate.

I’m not terribly disappointed by the lemon grass, but I was rather attached to that lemon bush. The only compensation is that now there’s room for the Ladies of the Night (Cestrum nocturnum) in the window; it was languishing a bit before, but it’s already started to perk up.